Hypoxia is indeed a hard signfor most events of major pulmonary embolism . It can even be termed as an essential criteria .A hypoxic , tachypenic patient in sinus tachycardia with echo evidence of new onset RA or RV dilatation is almost 100 % specific for acute pulmonary embolism . ( This becomes 200 % if he or she has DVT as well !)

Cardiologists are closing in , trying to capture the final frontiers. The trans-cutaneous Aortic valve Implantation now has a two year follow up. (NEJM March 2012 Issue) . The results are encouraging .

While two companies are fighting for the supremacy in TAVI , the real threat is for the cardiac surgeons. Currently Edward Sapiens has an edge over Medtronic core valve as it has a provision to redeploy or fine-tune the final geo- position.

We owe a lot to our past genius minds for our current understanding of cardiology.Youngsters should know how the filed of cardiology evolved .Few great brains taught us how to think hemodynamically in the setting of STEMI.

The Diamond and Forrester classification is an undisputed achievement of modern cardiac hemodynamics.They gently converted the clinical classification of Killip into more scientific hemodynamic one .Both these classification continue to fascinate us even in the era of instant PCI for STEMI .

And youngsters should read this again and again and critically evaluate their patients within this system.The two key parameters he used was PCWP of 18mmhg /And cardiac Index 2.2liters . He also suggested a simplified version where intra- arterial monitoring is not feasible. The cardiac Index could be replaced by systemic blood pressure lung congestion represents PCWP >18mmhg .

The DF classification would become

An important inference from DF classification !

The class 3 of DF grading has no pulmonary congestion but persistent hypotension . What does it mean ?

It is a stunning proof of a great concept. As the patient moves (Worsens) from DF two to DF three ,the lung congestion tends to regress . This sub-set actually means development of bi-ventricular failure or isolated RV failure . This is an ominous sign and indicate a bad prognosis . ( One may call it a paradox , according to conventional thinking “The more the lung crackles , dismal is the outcome” DF grading clearly proves this is not always true , as long as the systemic pressure is maintained crackles can be managed effectively . In DF 3 the right ventricle as a pump is becoming so weak it is not able to congest the lungs at the same process leads to systemic hypotension.

Forrester is also a pioneer in how we evaluate chest pain in the emergency rooms and cardiology OPDs . His thoughts on utilization of Besean theorem revolutionized the interpretation of exercise stress testing.

The entity of stress cardiomyopathy , other wise referred to as Takotsubo cardiomyopathy is a popular clinical entity in recent decades.The heart and mind are closely linked entities even though they are situated apart physically . Extensive neural and hormonal control mechanisms exist.

In extreme stress ,the hyper- sympathetic drive triggers a rush of adrenaline , which some how makes the left ventricle to bulge out !

The clinical features are varied .

It can exactly mimic an acute coronary syndrome .

ECG may show ST elevation and mimic an anterior STEMI

Echo shows a wall motion abnormality classically described as the apex alone dilates /Bulges or elongates

LV may acquire a shape of a banana. (See below )

A 45 year old man came to the ER with severe chest pain , dyspnea and minimal ST elevation in anterior leads. He was a smoker and was experiencing recent major office stress . Echo showed an elongated LV apex with some thinning .We made a diagnosis of stress cardiomyopathy .( It was disputed by my professor as the LV apex was contracting well ! but we learnt later there are many varieties of Takatsubo )

Echo showed an elongated LV apex with some thinning . Note the LV apex goes out of plane with RV apex.

Color Doppler revealed Trivial Mitral regurgitation

Follow up

He underwent coronary angiogram. Had no significant lesions , in 48 hours time the wall motion defect disappeared and was discharged with beta blockers.

Incidence

Up to 2 % of ACS could be related to Takatsubo . More common in women especially post menopausal , with stressful/emotional background like loss of loved ones.

Synonyms

Apical ballooning , Broken heart syndrome , Stress cardiomyopathy.

Mechanism

Not clear . Microvascular spasm , excessive catecholamines , are thought to be major culprits.

Irregular wide qrs tachycardiais a fairly common clinical entity in any cardiac emergency room. The moment you ask about such tachycardia , 9/10 fellows will come out with a prompt answer ” AF with WPW syndrome” even before you complete the question ! It is not that common as we perceive .The problem is with our traditional teaching methods and the attraction of human brains to rare and exotic disorders.

traditionally SVT with aberrancy is diagnosed mainly in the setting of regular tachycardia .

We often forget “AF with aberrancy” is equally common , and it presents with a irregular wide qrs tachycardia .

I wonder whether this phenomenon can be termed as orthodromic aberrancy .This can directly compete in the differential diagnosis of antidromic AF with WPW !

It should also be mentioned antidromic AF can run into very high rates as accessory pathways do not check the incoming signals while orthodromic aberrancy the ventricular rates can not exceed 220 or so at least theoretically . (This simple clue can clinch the issue in favor of WPW )

There is no proper published data available for the true incidence of AF with orthodromic aberrancy in general population

In fact , there are many electrical environments for AF to become a wide qrs AF

1. AF with Antidromic conduction through accessory WPW pathway.

2. AF with Orthodromic aberrancy ( Non WPW – Similar to any SVT with aberrancy )

There are many causes for wide qrs tachycardias in Atrial fibrillation . WPW with anti-dromic conduction is just one of them .We need to approach the issue with an open mind .Please be reminded , once contemplated WPW syndrome can be a powerful thought blocker !

Note : *We are not including polymorphic ventricular tachycardia here .It is an important subset of wide qrs irregular tachycardia.

** VT can co-exist with AF .This is not surprising as many of the diffuse cardiomyopathies involve both atria and ventricle with extensive scarring and fibrosis a perfect trigger for both atrial and ventricular arrhythmias .

Interventions in Eisenmenger syndrome or severe PAH in left to right shunt continues to be a major diagnostic issue.The challenge lies not only in assessing whether the progression of PAH can be prevented by blocking the left to right shunt , but also to assess it’s impact on survival.

The factors involved are

Pulmonary artery pressures

Pulmonary blood flow

Pulmonary vascular resistance

RV function

Co-morbid /general condition of the patient

While cardiologists worry more about LV , surgeons have different issue . In left to right shunts with PAH RV function bothers them more , as the high pulmonary artery pressure may never allow the surgeons to come off the pump , once the decompression provided by ASD/ VSD is removed

How relevant is Ohm’s Law in complex shunt with leaky valves and bidirectional shunting ?

The fundamental hemodynamic equation is derived from Ohm’s law .How relevant is Ohm’s law in Eisenmenger is not clear. For decades we have been using complicated calculations with many presumed and assumed parameters. The calculation of effective pulmonary blood flow in bidirectional shunt may be most complex equation in clinical cardiology. One can only imagine how one error could amplifies the other.

The hemodynamic equivalent of Ohm’s law states

R = Pressure / Flow .The current thinking is If the PVR is between 6-8 it is operable .

Is it really that simple ?

We know pressures can be measured with a fair degree of accuracy . Flow and resistance are subjected to change in a moment to moment basis .They are determined by a gamut of neural and humoral factors.

Ironically , we are not yet clear , whether flow determines the pressure or pressure determine the flow .

The right heart blood flow can get complicated by not only bi-directional shunt but also by pulmonary and tricuspid regurgitation ,

There is a huge perception problem here . We are tuned to think , reversibilty of PAH is same as operability of shunt lesion . Definitively not ! This is the reason why there is a vast difference in ultimate outcome with little correlation with PVR !

Above all a harmonious Cardiologist – Cardiac surgeon team is vital to plan this complex surgery

So, now it would seem cath studies are primarily done for academic pursuit , and it rarely helps in genuine decision-making process.

The following table synthesized in our hospital (Mainly with clinical data ) can be a useful tool.

Reference: Learnt in the bedside from poor children of India

We had a situation like this . A patient was in class 3 or 4 and calculated PVR was less than 6 Wood units what will you do ?

Never give importance to numbers . These patients will 99% of times won’t survive a shunt closure surgery.

Future development

With the availability of modern drugs like Nitric oxide, prostocyclins, Sildenafil analogues medical management has a potential to improve upon surgical results. Unfortunately large studies are not possible in these population . In the surgical front, fenestrated VSD closures peri-operative intensive nitric oxide show some promise.

Final message

I think we are about to say a final good-bye* to oxymetry ( or even cath study ) in the work up of PAH due to shunts.

*Still, pressures of right heart chambers and pulmonary artery is vital .Echo can not be expected to provide accurate measure of PA pressure .(Even though there some echo studies available to calculate qp/qs and PVR non invasive)